iPhone wall adapter not fast charging

Symptoms

• Charging speed feels the same as an old, basic adapter
• No noticeable difference in charge time after buying a 'fast charger'
• Charging works but slowly with a higher-wattage adapter
• Fast charging worked before but has since slowed down

Likely causes

• CommonCable not rated for fast charging power levelsA basic USB-A to Lightning cable, for example, cannot carry the higher wattage needed for fast charging even with a good adapter.
• CommonAdapter wattage below the 20W minimum most iPhones need for fast chargingFast charging on most models requires at least a 20W USB-C power adapter.
• PossiblePhone already at a high percentage where charging naturally slowsFast charging is most noticeable in the first 50%; the last portion always charges more slowly regardless of adapter.
• PossibleUsing the phone actively while charging, offsetting fast charging gainsHeavy use during charging reduces the net charge rate you'll notice.

What to do

1. Confirm the adapter is rated 20W or higher and outputs via USB-C.
2. Use a USB-C to Lightning or USB-C to USB-C cable rated for fast charging, not a basic USB-A cable.
3. Test charging from a low percentage, like under 20%, to see the fast-charging effect most clearly in the first 30 minutes.
4. Avoid using the phone during the test, since active use reduces the effective charge rate.
5. Check that the adapter and cable are both genuine or certified, since mismatched or low-quality parts can bottleneck speed.
6. Try the exact combination Apple sells together if uncertain, since it's guaranteed compatible.
7. Note that charging naturally slows above 80% regardless of adapter wattage, which is expected.
8. If speed is still slow with a confirmed correct adapter and cable, check the phone's port or battery health.

Tools and parts

When to call a pro

This is usually solved by matching the right adapter and cable; if fast charging still doesn't work with confirmed correct accessories, have the port checked.

Safety